Hear me out; illiterate/semi-illiterate city-elf Warden.
Education is already questionable for commoners, elves in the alien age even worse. It’s not all that strange for a tabris warden who only knows how to read/write a few things, probably only learned what was required for wherever they worked.
Then they join the wardens, and everyone just assumes that tabris can read just as well as the next guy. And Tabris goes with it, and does a lot of bluffing and bullshitting so people don’t think otherwise.
Alistair- You read those treaties, right?
Tabris- *nervous laughter* what? Psh, of course I did. But it was— you know so much happened since I did. Ostegar. Darkspawn. Maybe refresh my memory. I don’t need it, but you explain things better than I.
Finds Rigby and Jogbys letters and is just “yes I know exactly what this says” and just stumbled across both the meeting spot and cache by absolute chance, so Jory and Daveth just praise them thinking Tabris had found them by following the letters.
Morrigan is the only one to know. Has know from the very start. Tabris doesn’t know she knows, they are suspicious, but she does nothing to confirm, but she occasionally makes a remark or a request about them reading something and just the raw anxiety as they try to find their way out of her trap without making others suspicious.